Sprayer



Jan. 2.8, 19,30. T. BIRKENMAIER I 1,744,861

SPRAYER Filed Nov. 4, 1927 2 Sheets-Sheet l Jan. 28, 1930. i T. BIRKENMAIER 1,744,851

SPRAYER Filed Nov. 4, 1927 2 Sheets-Sheet 2 tem, such that the liquid Patented Jan. 28, 1930 unirse ls'rarss PATENT erstes THEODORE BIRKENMAIER, OF ST. LOUIS, MISSOURI, ASSIGNOR TO W. N. MATTHEWS CORPORATION, OF ST. LGUIS, MISSOURI, A CORPORATION OF MISSOURI SPRAYER Application led November This invention` relates to sprayers and with regard to certain more specific features, to control means for paint spraying systems.

Among the several objects of the invention may be noted the provision of means for controlling the flow of air and liquid in a pressure operated and airagitated sprayer syswill be at all times, and under all conditions of operation, prevented froni flowing abnormally, that is, from flowing so as to detrimentally flood certain portions ofthe apparatus; and the provision of means of the class described which is positive and automatic in its operation and which is simple to manufacture, install and Operate and which is rugged in construction. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combination of elements, features of construction, and arrangements of parts which will be exemplified in the struc ture hereinafter described, and the scope of the application of which will be indicated in A th following claims.

In the accompanying drawings, in which IS ments of the invention,

- Fig. 1 is a plan view of certain paint spraying equipment embodying the invention;

Fig. 2 is a front elevation of Fig. 1, certain portions being broken away;

Fig. 3 is a cross section showing a typical pressure regulating valve;

Fig. 4 is a fragmentary section showing a portion of a typical fixed pressure reducing valve; and

.ti h t l Flg 5 1S a Cross Sec lon s Owmg a Ypma phragm 41 1s normally pushed downwardly air control valve.

Similar .reference characters indicate corresponding parts throughout the several views of the drawings. i Y

Referring now more particularly'to Figs.

" 1 and 2, there is illustrated at numeral 1 a lid of a paint'pot 3, adapted to be held toy said pot by swingable draw` bolts 5. The lid 1 and the pot 3 are adapted to be engaged in air tight fashion, as shown in the figures, or disengaged, by loosening thumb screws 7 of illustrated one of rvarious possible embodi- 4, 1927. Serial N0. 230,951.

said bolts 5, swinging the bolts aside and lift-V ing said'lid or cover 1.

The pot or container 3 is adapted to receive liquidto be sprayed, such as paint or the like. v

also has bolted thereto by means of a stud j 13 a Xed pressure reducing valve 15. These valves 11 and 15 are supported more rigidly by fastening them together with a connector 17, which connector 17, however, does not serve to interconnect any of the air chambers of said valves, that is, it does not operably connect them.

The air presure regulator 1-1 is mounted on the cover 1, merely for convenience in operating the equipment. It is provided with an inlet line 19 leading from la stop cock 21, the latter being adapted to be connected with an air line from a suitable compressor (not shown). This regulator is also provided with an outlet leading to a manifold 23 hav-` ing stop cocks 25 adapted to be connected with air lines leading to conventional air connections'of certain spray guns (not shown). A suitable gage 26 is used in the manifold 23.

The purpose of the regulator 11 is to adjustably control the pressure of the air which is being delivered to the air connections of said guns, the from a control handle 27.

Fig. 3 shows the construction of the regulator 11 which comprises a casing 29`having an inlet 31 and an outlet 33. Air in passing from the inlet to the outlet traverses a valve 35 which is equipped with a closure element 37 held in a saddle piece 39, the latter connecting with an upper diaphragm 41. The diaby means of a spring 43 reacting from the adjusting handle 27. A small closing spring 45 is used for lightly holding the valve 35 closed when the spring 43 is adjusted for zero pressure.

The operation of the regulator 11 is as follows:

Air under pressure entering the inlet 31 passes through the valve 35, actuating the light spring 45 to open the valve if the handle 27 .is not set for some pressure reduction.

adjustment being made ico There being a space connecting the valve chamber 45 and the diaphragm chamber 17, the air `enters the diaphragm chamber and passes out of the outlet 33.

As long as the air pressure at the outlet is under a predetermined pressure, governed by the handle 27 and the springl L13, such as say pounds per square inch, air will continue to flow through the regulator; but when the pressure builds up in the outlet, the pressure beneath the diaphragm will build up, thereby causing the valve closing member 37 to close the valve 35, the diaphragm and member 37 being connected by said saddle piece 39. Then the pressure goes below the predetermined amount, the valve will again be opened, due to the action of spring 43. Any desired pressure within the range of the device may be maintained at the cocks 25, merely by adjusting the handle Q7.

The reducing valve 15, shown partially in Fig. 4, is also provided with pressure reducing elements but the amount of pressure reduction cannot be adjusted and this valve therefore is not a regulator but a mere pressure reducer. In the case of reducing valve 15, the spring 43a reacts against a fixed screw 49, which is applied at the factory and soldered as at 51, so that it cannot be regulated, the fixed pressure used in the present example being 40 pounds per square inch. The purpose of this will be shown hereinafter.

Referring again to Figs. 1 and 2, it will be seen that the inlet line 19 from the compressor carries a branch 53, the purpose of which is to provide means for fastening air accessories such as a pressure blower or the like for cleaning and like purposes.

Leading from and communicating with lines 19, 53 is a direct high pressure air line 55 which leads into the inlet side 57 of an air control valve 59 (see also Fig. 5).

The control valve 59 comprises a body 61 having a hollow chamber 63 formed with a nozzle 65 communicating with said inlet 57 A rubber or other suitable diaphragm 67 is normally held in a position adapted to close the nozzle 65 by means of a spring actuated stem 69 aligned by a hollow sleeve 71. The spring 73 pressing the stem 69 is adjustably tensioned by an adjusting screw 75. The closed position of the diaphragm is shown by dotted lines in Fig. 5 and an open position by solid lines. A

The operation is such that when air, say above L15 pounds pressure enters, the tension of the spring is set so that the valve will open and remain open, thereby permitting air to pass through the control valve. But when the pressure drops, say to 45 pounds, the action of the spring overcomes the pressure under the diaphragm and closes the valve, thereby preventing air from flowing forward or counter to the direction intended. It will be seen hereinafter that this valve differs from a check valve in that it will permit a re versal of flow down to a predetermined pressure at its outlet, whereas a check valve would not do so but close upon every reversal.

From the outlet 77 of the control valve 59, the air flows to the reducer 15 by way of a line 79. It passes through said reducer 15 and in the present example, is reduced in pressure to say Ll0 pounds. From the reducer 15, the air is conveyed to an inlet stop cock 81 by way of a line 83, said line 83 carrying a gage 85 for the purpose of ascertaining whether or not the reducer 15 is at all times in working order. The stop cock 81 communicates with a stand pipe 87 of an agitator ing 89 located in the bottom of pot 3. r1`he agitator ring 89 is provided with outlet openings 91 for permitting bubbling of air through the liquid or paint in the container 3. The ring S9 is braced to the cover 1 by means of a supporter 93 held by said stud 9. The bubbling of the air through the paint provides the desirable agitation.

The air pressure on the paint in the container 3 tends to force it up a tube 95 fastened to said cover 1 and communicating with an outlet volume control valve 97. This volume control valve consists of a stem 99 movable across the outlet passage 101 through the valve, and having various sized openings 103 therein, adapted to permit various volumes of paint to pass, depending upon the lateral setting of the stem. This valve 97 incorporates a stop cock 98.

The volume control 97 is adapted to be connected with a material line passing to the gun or guns or sprayers receiving atomizing air from the stop valves 25.

The cover 1 carires thereon a relief valve 105, a safety valve 107 and a handle 108.

The operation of the invention is as follows:

High pressure air, say at 100 pounds per square inch, is introduced at the cock 21 and a part thereof passes to and through the pressure regulating valve 11 and thence to the stop valves 25 by way of said manifold Q3, registering on the gage 26. From the stop valves 25 this portion of the air is led to the air passages of the spraying instrument, such as an air gun. The pressure regulator 11 may be assumed to be set so as to reduce from onehhundred to, say 8O pounds per square mc Another portion of the 100 pounds per square inch air from the cock 21 passes over the line 53 and thence down through the high pressure line 55 to the control valve 59. Assuming that the control valve 59 is set for 45 pounds pressure, this 100 pounds per square inch, high pressure air will pass therethrough, through the line 79 and to the fixed pressure reducing valve 15 which is assumed to he set for a reduction to 40 pounds per square inch.

`to the p., .pressure reducer v'and upon subsequent operation,

any other apparatus connected tates a cleaning,

described are Air at the reduced pressure of pounds per square inch will then flow over the line 83, registering on the gage V85, and if the cock 81 is open, will pass down the stand pipe 87 agitating ring 89. From container 3. The liquid in the container kbeing under this 4() pounds per square inch pressure will be forced up the pipe 95 and ,through the volume control valve 97 and to 'the spraying device by means of a suitable line. l

It has heretofore been found that if the control valve 59 be omitted, that upon reducing the pressure in the high pressure inlet lines,

tank pressure (40 pounds per square inch) that the internal tank pressure will then push paint back up through the agitator, line 83, and lines 55, 53 and 19 the paint may even be driven through the regulating valve 11 and to the air passages of the gun or guns. The paint also gets into the gages and with these lines. Needless to say, this result is detrimental to the equipment, because apparatus constructed for operation by air, will not withstand the encrusting, corroding and clogging action of the paint, or at least a complete dismantling, cleaning and overhauling operation is required.

Furthermore, when paint passes through the air passages of a gun, it not only necessibut detrimentally affects the action of the gun and consequently'also detrimentally atiects the surfacel being coated.

^ Some of tbe reasons for the pressure dropping in the high pressure lines in the manner that the compressor may fail, the line from the compressor joining with the stop cock 21 might be accidently or other; wise disconnected without shuting off said stop cock 21, or the rate of sprayingwith the spraying apparatus may be such as to momentarily draw air at a greater rate than air is being supplied by the compressor, hence reducing the high pressure to a value below the pressure in the pot. Other reasons may iarise or present themselves.

It will be seen that the present invention overcomes the above difficulties, because when the value of the pressure of the air in Y the high pressure lines such as 19, 53, 55 drops below the value of the pressure in the tank, this implies that said reduced value of the ordinarily high pressure is below that re? quired to hold open the control valve 59, said Y v. control valve being set for a slightly higher pressure than the pressure on the low side of the reducing valve 15. The result is that the valve 59 cuts off any counterflow and maintains a pressure on the high side of the reducing valve 15 which is at least equal to or thence it' will "bubble out and up through the liquid in the greater than the pressure on the low side of said pressure reducer 15;

It is to be understood that the pressure control yvalve 59 may be set to pass pressures either approximately equal to the pressure carried in the tank or above said tank pressure.

In the present embodiment, in which the control valve 59 permits passage of air at a pressure greater than the pressure on the low side of the reducer 15, there is provided a tive pound diii'erential for permitting continuous operation of the reducer 15 during momentary decreases of the inlet pressure.

YVF rom the above it will be seen that this invention provides uninterrupted and continuously smooth operation, regardless of fluctuations in the pressure of the air supplied y.

to the device.

The advantage ofthe diaphragm valve 59 over an ordinary check valve is that for variations of pressure above forty-live pounds the diaphragm valve does not continuously open and close or flutter as would a check valve under the same conditions. The diaphragm valve remains open and provides exceedingly smooth action.

Another advantage is that valve responds in the same manner under all positions thereof, tilted or otherwise,while a check valve has different characteristics of operation, depending upon its particular position. It is to be remembered that tanks of this class do not always stand level.

Another important advantage is that in the case of anvordinary check valve, if the pressure between it and the reducing valve 15 happened to leak down to a value at or below the pressure in the line 55 (and the pressure in the line 55 were subnormally below 40 pounds) then' the Ll0 pounds pressure in the tank would back the liquid up detrimentally against the low inlet pressure which the difwould result onlyin an yincipient movementv of said paint, because the displacement in the line k7 9, reducer 15 and line 83 is so small that the paint -wouldnot proceed far.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. Y

As manyvcha-nges could be madey in carrying out the above constructions without departing from the scope of the'invention, it is intended that all matter contained in theabove description or shown in the accompany-- f the diaphragm ing drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In liquid spraying equipment, a tank carrying a liquid supply, means for introducing air under pressure to a point below the level of said liquid supply comprising an air line having an inlet, a pressure reducer in said air line set to provide a pressure within said tank below the inlet pressure of said air line and a control valve between said inlet and said reducer operable to permit passage of air above a predetermined pressure to said reducer, said predetermined pressure being at least equal to said pressure within the tank but lower than said inlet pressure.

2. In liquid spraying equipment, a tank carrying a liquid supply, means for introducing air under pressure to a point within the tank comprising an air line having an inlet, a pressure reducer in said air line and a valve between said inlet and said reducer adapted to check at least some air at predetermined inlet pressures.

3. In liquid spraying equipment, a tanl carrying a liquid supply, means :tor introducing air under pressure to a point below the liquid level within the tank comprising an air line having an inlet, pressure reducing means in the air line and a diaphragm valve between said inlet and said reducer adapted to prevent backing of liquid to said reducer when pressure in said line falls below the pressure in the tank.

4. In liquid spraying equipment, a tank carrying a liquid supply, means for introducing air under pressure to a point below the liquid level within the tank comprising an air line having an inlet, pressure reducing means in the air line and means located between said inlet and said reducer adapted to revent backing of liquid to said reducer when pressure in said line falls below the pressure in the tank.

5. In liquid spraying equipment, a tank carrying a liquid supply, means for introducing air under pressure to a point within the tank comprising an air line having an inlet-,a pressure reducer in said air line and a valve between said inlet and said reducer adapted to check the return of any air when the inlet pressure drops below a predetermined amount but permitting return above said predetermined amount of pressure.

6. In liquid spraying equipment, a tank carrying a liquid supply, means for introducing air under pressure to a point within the tank comprising an air line having an inlet, a pressure reducer in said air line and a valve between said inlet and said reducer adapted to check the return of any air when the inlet pressure drops below a predetermined amount but permitting return above said predetermined amount ot pressure, said predetermined amount of inlet pressure eing greater than the reduced pressure within the tank.

7. In liquid spraying equipment a tank carrying a liquid Supply, means for introducing air under pressure, to a point below the liquid level in the tank comprising an air line having an inlet, a pressure reducer in said air line and a valve between said inlet and said reducer adapted to permit passage of air to and from the reducer when said air is above a predetermined pressure but preventing passage of air to and from said reducer when said air is below said predetermined pressure.

8. In liquid spraying equipment a tank carrying a liquid supply, means for intro ducing air under pressure, to a point below the liquid level in the tank comprising an air line having an inlet, a pressure reducer in said air line and a valve between said inlet and said reducer adapted to permit passage of air to and from the reducer when said air is above a predeterminedA pressure but preventing passage oi' air to and from said reducer when said air is below said predetermined pressure, said predetermined pressure being higher than that for which the reducer is set.

9. In liquid spraying equipment a tank carrying a liquid supply, means for introducing air under pressure, to a point below the liquid level in the tank comprising an air line having an inlet, a pressure reducer in said air line and a valve between said inlet and said reducer adapted to permit passage of air to and from the reducer when said air is above a predetermined pressure but preventing passage of air to and from said reducer when said air is below said predetermined pressure, said predetermined pressure being at least equal to that for which the reducer is set.

In testimony whereof, I have signed my name to this specification this 1st day of November, 1927.

THEODORE BIRKENMAIER. 

